In gas turbine engines, a portion of the total airflow from the compressor may be diverted to cool various turbine components. Specifically, a flow of bleed air may be extracted from a stage of the compressor to cool a stage of the turbine or other components. This diverted airflow, however, may consume a significant portion of the total airflow through the compressor. The management and control of these parasitic airflows thus may increase the overall efficiency and performance of the gas turbine engine.
The airflow extractions from the compressor may be controlled by one or more control valves positioned on the air extraction lines. The actuators for these control valves and other types of control valves may be mounted within the high temperature environment of a gas turbine enclosure. Given this environment, the control valve actuators may be positioned within a radiation shield and the like so as to mitigate the impact of the high temperatures. These radiation shields, however, may not properly protect the control valve actuators from convective heating that may be present within the enclosure. Forced air cooling from a blower or an air compressor may assist in cooling the control valve actuators. These cooling systems, however, also may be a parasitic drain on the overall operation of the gas turbine engine.
There is thus a need for an improved control valve actuator cooling system. Preferable such an improved cooling system may provide cooling to the control valve actuators without the use of complex components or parasitic airflows so as to provide increased reliability and efficiency with decreased overall costs.